Re: [Qemu-devel] [PATCH 2/2] hda: do not mix output and input stream states, RHBZ #740493

[Juan Quintela <quintela@redhat.com>]

"Marc-André Lureau" <marcandre.lureau@gmail.com> wrote:
> Windows 7 may use the same stream number for input and output.
> Current code will confuse streams.
>
> NB: I wonder if this patch breaks migration code because of
> this change:
> -        VMSTATE_BOOL_ARRAY(running, HDAAudioState, 16),
> +        VMSTATE_BOOL_ARRAY(running, HDAAudioState, 2 * 16),

It does :-(

Two questions to know how to handle this.
a) My understanding of this patch is that we move from an array of 16
bools representing anything to one array where the 1st 16 represent if
there are input and the 2nd 16's reprosenting if there are output for
that channel.

So, what we should do if we migrate from one old version that only has
16 bools?  My understanding is that copying directly is not gonna work?

b) Just in case it makes "compatibility" easier.

Is the running array normally all false or similar?  If so, we could
just sent the other 16th values only if they are different of false.
(if this is true, it is interesting to put in the 1st slots the ones
that are more probable to be true).

Later, Juan.